Mercury rectifier



Jan. 10, 1928.

L. T. ROBINSON MERCURY RECTIFIER Filed Nov. 18, 1925 Inventor: Lewis T. Robinson,

His Attorney.

Patented flan. 10, 1928.-

UNITED STATES PATENT OFFICE.

LEWIS T. ROBINSON, 0F SCHENECTADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC commutes CORPORATION or new YORK.

MERCURY RECTIFIER.

My invention relates to vapor electric devices comprising an electrode located within an evacuated container and connected to an external conductor through a lead sealed to the container wall. and has for its principal object the provision of an improved arrangement for protecting the seal between the lead and container wall from injury due to change in the temperature of the parts with which it is mechanically associated and for maintaining the electrode at a temperature ensuring proper operation of the device.

In the operation of a vapor electric device comprising a lead sealed to the wall of a container and connected between a fixed electrode located within the container and a conductor external thereto. difficulty in maintaining the seal between the lead and container wall is encountered due to unequal expansion and contraction of the parts mechanically associated with the seal. It has been proposed to avoid this ditliculty by inter-posing a flexible lead between the seal and electrode which is supported independently of the seal. In previous arrangements of this character, however, no provisions have been made for circulating a cooling medium in contact with the electrode.

It is important that the anode temperature of a vapor electric device, such as a mercury rectifier, be maintained within predetermined limits. If the anode temperature becomes too high, surface particles of the anode metal are vaporized and the resulting metal vapor both decreases the effectiveness of the insulation between the anode and its support and increases the vapor pressure in the vicinity of the anode to a value at which destructive arcs, commonly designated by the expression arc back, are likely to be produced. This difficulty is also likely to be encountered when the anode temperature is too low for the reason that mercury condensed on the cool areas of the anode surface flows down or drops on the hot areas of this surface and is vaporized, thereby producing local areas of high vapor pressure at the active surface of the anode. In accordance with my invention, these difficulties are avoided by the provision of a hollow lead which is interposed between the seal and electrode in a manner to form a flexible connection therebetween and to permit the circulation of a cooling medium My invention will be better understood I from the following description when considered in connection with the accompanying drawings and its scope will be pointed out in the appended claims.

Referring to the drawings, Figs. 1 and 2 are fragmentary sectional views of a mereury rectifier wherein my invention has been embodied; and 3 and 4 illustrate various details of an anode which may be utilized in connection with my invention.

Fig. 1 shows an anode 1 which is con nected to a conductor 2 through a hollow lead comprising a corrugated or flexible portion 3 and a rigid portion 4 provided with a flange 5. The anode 1 is supported by the cover 6, an insulator 7 and members 8 and 9 which are interposed between the flange 5 and the cover. At its upper end, the anode lead is insulated from the cover by a cylinder 10 of insulating material sealed at its upper end to a cap 11 and at its lower end to a flanged member 12 which rests upon the upper edge of the support member 9. Semi-circular members 13 slotted to receive the flanged edges of members 9 and 12 and provided with set screws 14 are rovided for clamping the flanges of mem ers 12 and 9 together to form a gastight joint. The cap 11 is welded or otherwise sccured to the electrode lead. With this construction the anode is suspended from the insulator 7 and the cylinder 10 of insulating material is protected from expansion and contraction of the parts by the bellows-shaped, flexible section 8 of the an ode lead.

As shown more clearly in Fig. 2, the anode 1 extends downwardly into the top of a cylindrical shield 15 which is cut away at its lower end on the side next to the wall of an evacuated container 16 surrounding the anode and comprising an insulated wall portion 17 whereon the mercury cathode 18 is supported. Any suitable means, such as chambers 19 and 20, may be provided for circulating a cooling medium in contact with the walls of the evacuated container.

Figs. 3 and 4 show different views of an anode which may be used in connection with the hollow, flexible lead previousl described. This anode comprises a cup-s aped surface21, cooling fins 22 which are shaped to radiate heat from the anode to the cool walls of the member 9, and a threaded portion 23 adapted to be screwed into the lower end of the hollow lead. A artition 24 may be rovided within the rigi portion 4 of the lead to facilitate the circulation of a cooling medium supplied through the upper end of the electrode from any suitable source.

B means of the partition 24, cross currents 0t the cooling medium are minimized and the heated medium tends to move higher up within the tubular portion 4 before it starts to return to-the lower end of this ortion. It will of course be apparent that, w ile but one anode-appears in the figures, the device will usually comprise either a pair of electrodes connected to the opposite terminals of a single phase source, or a plurality of 916C. trodes each connected to aditferent terminal of a polyphase source. It will also be apparent that a corrugated section similar to the section 3 may be interposed between a cooling fluid condenser located at the top of thelead and the seal. With this construc tion the condenser is mounted on a fixed support and the seal is protected against injury by the upper flexible section.

The embodiment of the invention illustrated and described herein has been selected for the purpose of clearly setting forth'the principles involved. It will be apparent, however, that the invention is susceptible of Leeaeav i being modified to meet the difierent conditions encountered in its use and I therefore aim to cover by the appended claims all modifications within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is: 0

1. The combination of a container, an electrode suipported within said container and insulate mm the wall thereof, and a tubular lead connected to said electrode and provided with a corrugated conductive section for transmitting current to said electrode, said lead being connected to said wall through means comprisin a glass-metal seal.

2. The combination 0 a container, an electrode supported within said container and insulated from the wall thereof, and a tubular lead comprising a corrugated conductive section interposed between said electrode and a vitreous seal forming a portion i of said wall;

3, The combination of an electrode, a tubular lead connected to said'electrode and provided with a corrugated section for absorbing the stresses incident to changes in temperature, and means for controllingthe circulation of a cooling medium through said lead into contact with a surface of said electrode and said section.

In witness whereof, I have hereunto set my hand this 17th day of November, 1925.

LEWIS T. ROBINSON. 

